This invention relates to a method of manufacturing a semiconductor device, which method comprises providing a semiconductor body having adjacent one major surface a device region bounded by an insulating region, providing an electrical connection to the device region by providing an activating layer on the one major surface, applying a flowable insulating material to form a layer on the one major surface, defining an opening through the insulating flowable material layer thereby exposing a contact area of the device region, and selectively depositing electrically conductive material into the opening to form a conductive pillar in electrical contact with the contact area.
Such a method is described in EP-A-0195977. As described in EP-A-0195977, the flowable insulating material comprises a layer of polyimide which is spun onto the one major surface so providing a relatively flat surface. An oxide layer is provided on the polyimide layer and is followed by a photosensitive resist which is developed to form the masking layer through which the insulating flowable material layer is etched using a wet or a dry etchant. Tungsten is then selectively deposited to form the conductive pillar in the opening etched in the dielectric by chemical vapour deposition using WF.sub.6 and H.sub.2. In order to facilitate tungsten deposition by using, for example, a lift-off technique, an activating or nucleation layer is provided in the opening. After formation of the conductive pillar, a further layer of polyimide is spun onto the surface and the above-mentioned steps repeated. Where it is desired, as shown in FIG. 8 of EP-A-0195977, to interconnect two or more pillars by a second metallization level, then a nucleation layer will normally be required to enable selective deposition of tungsten over the first polyimide layer. This process may be repeated one or more further times depending on the desired number of metallization levels. This method relies on the spun-on polyimide layers to provide the insulating or dielectric material which isolates conductive pillars from one another so that only the desired electrical connections are made. Polyimide is, however, susceptible to cracking and contamination and therefore may not provide sufficiently good insulation so that short-circuits may, for example, occur.